I was going to post something on the story about
underwater
robots, but I can't because of this wacky certification
mechanism. Anyway, I was going to write about
Attitude Heading Reference sensors, which typically combine
a three axis flux gate magnetometer, rate gyros and
accelerometers. They do internal filtering and output
angles and angle rates for yaw, pitch and roll. Two small
sub-$2k devices on the market that we are currently
evaluating:InertiaCube23DM-G